Multi-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/949,532 filed on Jul. 13, 2007. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having nineor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches or brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

An embodiment of the transmission includes an input member, an outputmember, first, second, third and fourth planetary gear sets each havingfirst, second and third members, a first interconnecting membercontinuously interconnecting the second member of the first planetarygear set with the second member of the second planetary gear set, asecond interconnecting member continuously interconnecting the thirdmember of the first planetary gear set with the first member of thesecond planetary gear set, a third interconnecting member continuouslyinterconnecting the third member of the second planetary gear set withthe first member of the third planetary gear set, a fourthinterconnecting member continuously interconnecting the second member ofthe third planetary gear set with the third member of the fourthplanetary gear set, and a fifth interconnecting member continuouslyinterconnecting the third member of the third planetary gear set withthe second member of the fourth planetary gear set. Six torquetransmitting mechanisms are selectively engageable to interconnect oneof the first members, second members, and third members with at leastone of the first members, second members, third members, and astationary element. The torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least nineforward speed ratios and at least one reverse speed ratio between theinput member and the output member.

In one aspect of the present invention, a first of the six torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the input member, the third member of the first planetarygear set, and the first member of the second planetary gear set with atleast one of the second member of the third planetary gear set and thethird member of the fourth planetary gear set.

In another aspect of the present invention, a second of the six torquetransmitting mechanisms is selectively engageable to interconnect atleast one of the input member, the third member of the first planetarygear set, and the first member of the second planetary gear set with thefirst member of the fourth planetary gear set.

In yet another aspect of the present invention, a third of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe first member of the first planetary gear set with the stationaryelement.

In yet another aspect of the present invention, a fourth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the second member of the first planetary gear set andthe second member of the second planetary gear set with the stationaryelement.

In yet another aspect of the present invention, a fifth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the third member of the second planetary gear set andthe first member of the third planetary gear set with the stationaryelement.

In yet another aspect of the present invention, a sixth of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the second member of the third planetary gear set andthe third member of the fourth planetary gear set with the stationaryelement.

In yet another aspect of the present invention, the first members aresun gears, the second members are carrier members, and the third membersare ring gears.

In yet another aspect of the present invention, the input member iscontinuously interconnected with at least one of the third member of thefirst planetary gear set and the first member of the second planetarygear set and wherein the output member is continuously interconnectedwith at least one of the third member of the third planetary gear setand the second member of the fourth planetary gear set.

In yet another aspect of the present invention, four of the torquetransmitting mechanisms are brakes and two of the torque transmittingmechanisms are clutches.

In yet another aspect of the present invention, the stationary elementis a transmission housing.

Another embodiment of the transmission of the present invention includesan input member, an output member, first, second, third and fourthplanetary gear sets each having a sun gear, a carrier member, and a ringgear, wherein the input member is continuously interconnected with atleast one of the ring gear of the first planetary gear set and the sungear of the second planetary gear set and wherein the output member iscontinuously interconnected with at least one of the ring gear of thethird planetary gear set and the carrier member of the fourth planetarygear set, a first interconnecting member continuously interconnectingthe carrier member of the first planetary gear set with the carriermember of the second planetary gear set, a second interconnecting membercontinuously interconnecting the ring gear of the first planetary gearset with the sun gear of the second planetary gear set, a thirdinterconnecting member continuously interconnecting the ring gear of thesecond planetary gear set with the sun gear of the third planetary gearset, a fourth interconnecting member continuously interconnecting thecarrier member of the third planetary gear set with the ring gear of thefourth planetary gear set, and a fifth interconnecting membercontinuously interconnecting the ring gear of the third planetary gearset with the carrier member of the fourth planetary gear set. A firsttorque transmitting mechanism is selectively engageable to interconnectat least one of the input member, the ring gear of the first planetarygear set, and the sun gear of the second planetary gear set with atleast one of the carrier member of the third planetary gear set and thering gear of the fourth planetary gear set, a second torque transmittingmechanism is selectively engageable to interconnect at least one of theinput member, the ring gear of the first planetary gear set, and the sungear of the second planetary gear set with the sun gear of the fourthplanetary gear set, a third torque transmitting mechanism is selectivelyengageable to interconnect the sun gear of the first planetary gear setwith a stationary element, a fourth torque transmitting mechanism isselectively engageable to interconnect at least one of the carriermember of the first planetary gear set and the carrier member of thesecond planetary gear set with the stationary element, a fifth torquetransmitting mechanism is selectively engageable to interconnect atleast one of the ring gear of the second planetary gear set and the sungear of the third planetary gear set with the stationary element, and asixth torque transmitting mechanism is selectively engageable tointerconnect at least one of the carrier member of the third planetarygear set and the ring gear of the fourth planetary gear set with thestationary element. The torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least nineforward speed ratios and at least one reverse speed ratio between theinput member and the output member.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a nine speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a nine speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the various embodiments ofthe nine speed automatic transmission of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. A second component or element of the firstplanetary gear set is permanently coupled to a second component orelement of the second planetary gear set. A third component or elementof a first planetary gear set is permanently coupled to a thirdcomponent or element of a second planetary gear set. A first componentor element of the second planetary gear set is permanently coupled to afirst component or element of a third planetary gear set. A secondcomponent or element of the third planetary gear set is permanentlycoupled to a first component or element of the fourth planetary gearset. Finally, a third component or element of the third planetary gearset is permanently coupled to a second component or element of a fourthplanetary gear set.

Referring now to FIG. 1, an embodiment of a nine speed transmission 10is illustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear set are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear, one for the planet gearcarrier, and one for the ring gear. The relative length between thenodes of each lever can be used to represent the ring-to-sun ratio ofeach respective gear set. These lever ratios, in turn, are used to varythe gear ratios of the transmission in order to achieve appropriateratios and ratio progression. Mechanical couplings or interconnectionsbetween the nodes of the various planetary gear sets are illustrated bythin, horizontal lines and torque transmitting devices such as clutchesand brakes are presented as interleaved fingers. If the device is abrake, one set of the fingers is grounded. Further explanation of theformat, purpose and use of lever diagrams can be found in SAE Paper810102, “The Lever Analogy: A New Tool in Transmission Analysis” byBenford and Leising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the third node 14C of the firstplanetary gear set 14. The output member 22 is coupled to the secondnode 20B of the fourth planetary gear set 20. The second node 14B of thefirst planetary gear set 14 is coupled to the second node 16B of thesecond planetary gear set 16. The third node 14C of the first planetarygear set 14 is coupled to the third node 16C of the second planetarygear set 16. The first node 16A of the second planetary gear set 16 iscoupled to the first node 18A of the third planetary gear set 18. Thesecond node 18B of the third planetary gear set 18 is coupled to thefirst node 20A of the fourth planetary gear set 20. The third node 18Cof the third planetary gear set 18 is coupled to the second node 20B ofthe fourth planetary gear set 20.

A first clutch 26 selectively connects the third node 16C of the secondplanetary gear set 16 with the second node 18B of the third planetarygear set 18. A second clutch 28 selectively connects the third node 16Cof the second planetary gear set 16 with the third node 20C of thefourth planetary gear set 20. A first brake 30 selectively connects thefirst node 14A of the first planetary gear set 14 to a stationaryelement or a transmission housing 40. A second brake 32 selectivelyconnects the second node 14B of the first planetary gear set 14 to astationary element or transmission housing 40. A third brake 34selectively connects the first node 16A of the second planetary gear set16 to the stationary element or transmission housing 40. A fourth brake36 selectively connects the first node 20A of the fourth planetary gearset 20 to the stationary element or transmission housing 40.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the nine speed transmission 10 according to thepresent invention. In FIG. 2, the numbering from the lever diagram ofFIG. 1 is carried over. The clutches, brakes, and couplings arecorrespondingly presented whereas the nodes of the planetary gear setsnow appear as components of planetary gear sets such as sun gears, ringgears, planet gears and planet gear carriers.

For example, the first planetary gear set 14 includes a sun gear member14A, a planet gear carrier member 14B and a ring gear member 14C. Thesun gear member 14A is connected for common rotation with a first shaftor interconnecting member 42. The ring gear member 14C is connected forcommon rotation with the input member 12. The planet gear carrier member14B rotatably supports a set of planet gears 14D (only one of which isshown) and is connected for common rotation with a second shaft orinterconnecting member 44. The planet gears 14D are each configured tointermesh with both the sun gear member 14A and the ring gear member14C.

The second planetary gear set 16 includes a sun gear member 16C, aplanet carrier member 16B that rotatably supports a set of planet gears16D and a ring gear member 16A. The sun gear member 16C is connected forcommon rotation with the input member 12 and with a third shaft orinterconnecting member 46. The planet carrier member 16B is connectedfor common rotation with the second interconnecting member 44. The ringgear member 16A is connected for common rotation with a fourth shaft orinterconnecting member 48 and with a fifth shaft or interconnectingmember 50. The planet gears 16D are each configured to intermesh withboth the sun gear member 16C and the ring gear member 16A.

The third planetary gear set 18 includes a sun gear member 18A, a ringgear member 18C and a planet carrier member 18B that rotatably supportsa set of planet gears 18D. The sun gear member 18A is connected forcommon rotation with the fifth interconnecting member 50. The ring gearmember 18C is connected for common rotation with a sixth shaft orinterconnecting member 52. The planet carrier member 18B is connectedfor common rotation with a seventh shaft or interconnecting member 54and with an eighth shaft or interconnecting member 56. The planet gears18D are each configured to intermesh with both the sun gear member 18Aand the ring gear member 18C.

The fourth planetary gear set 20 includes a sun gear member 20C, a ringgear member 20A and a planet carrier member 20B that rotatably supportsa set of planet gears 20D. The sun gear member 20C is connected forcommon rotation with a ninth shaft or interconnecting member 58. Thering gear member 20A is connected for common rotation with the eighthinterconnecting member 56. The planet carrier member 20B is connectedfor common rotation with the sixth interconnecting member 52 and withthe output member 22. The planet gears 20D are each configured tointermesh with both the sun gear member 20C and the ring gear member20A.

The input shaft or member 12 is preferably continuously connected to anengine (not shown) or to a turbine of a torque converter (not shown).The output shaft or member 22 is preferably continuously connected withthe final drive unit or transfer case (not shown).

The torque-transmitting mechanisms or clutches 26, 28 and brakes 30, 32,34, 36 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the seventh interconnecting member 54 with the thirdinterconnecting member 46. The second clutch 28 is selectivelyengageable to connect the ninth interconnecting member 58 with the thirdinterconnecting member 46. The first brake 30 is selectively engageableto connect the first interconnecting member 42 to the stationary elementor transmission housing 40 in order to restrict the sun gear member 14Aof the first planetary gear set 14 from rotating relative to thestationary element or transmission housing 40. The second brake 32 isselectively engageable to connect the second interconnecting member 44to the stationary element or transmission housing 40 in order torestrict the planet carrier member 14B of the first planetary gear set14 and the planet carrier member 16B of the second planetary gear set 16from rotating relative to the stationary element or transmission housing40. The third brake 34 is selectively engageable to connect the fourthinterconnecting member 48 to the stationary element or transmissionhousing 40 in order to restrict the ring gear member 16A of the secondplanetary gear set 16 and the sun gear 18A of the third planetary gearset 18 from rotating relative to the stationary element or transmissionhousing 40. The fourth brake 36 is selectively engageable to connect theeighth interconnecting member 56 to the stationary element ortransmission housing 40 in order to restrict the planet carrier member18B of the third planetary gear set 18 and the ring gear member 20A ofthe fourth planetary gear set 20 from rotating relative to thestationary element or transmission housing 40.

Referring now to FIGS. 2 and 3, the operation of the embodiment of thenine speed transmission 10 will be described. It will be appreciatedthat the transmission 10 is capable of transmitting torque from theinput shaft or member 12 to the output shaft or member 22 in at leastnine forward speed or torque ratios and at least one reverse speed ortorque ratio. Each forward and reverse speed or torque ratio is attainedby engagement of one or more of the torque-transmitting mechanisms (i.e.first clutch 26, second clutch 28, first brake 30, second brake 32,third brake 34, and fourth brake 36), as will be explained below. FIG. 3is a truth table presenting the various combinations of torquetransmitting mechanisms that are activated or engaged to achieve thevarious gear states. Actual numerical gear ratios of the various gearstates are also presented although it should be appreciated that thesenumerical values are exemplary only and that they may be adjusted oversignificant ranges to accommodate various applications and operationalcriteria of the transmission 10. An example of the gear ratios that maybe obtained using the embodiments of the present invention are alsoshown in FIG. 3. Of course, other gear ratios are achievable dependingon the gear diameter, gear teeth count and gear configuration selected.

To establish reverse gear, the first brake 30 and the fourth brake 36are engaged or activated. The first brake 30 connects the firstinterconnecting member 42 to the stationary element or transmissionhousing 40 in order to restrict the sun gear member 14A of the firstplanetary gear set 14 from rotating relative to the stationary elementor transmission housing 40. The fourth brake 36 connects the eighthinterconnecting member 56 to the stationary element or transmissionhousing 40 in order to restrict the planet carrier member 18B of thethird planetary gear set 18 and the ring gear member 20A of the fourthplanetary gear set 20 from rotating relative to the stationary elementor transmission housing 40. Likewise, the nine forward ratios areachieved through different combinations of clutch and brake engagement,as shown in FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the nine speed transmission 10 assumes, first of all,that all the clutches and brakes not specifically referenced in a givengear state are inactive or disengaged and, second of all, that duringgear shifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the second member of the first planetary gear set withthe second member of the second planetary gear set; a secondinterconnecting member continuously interconnecting the third member ofthe first planetary gear set with the first member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the third member of the second planetary gear set withthe first member of the third planetary gear set; a fourthinterconnecting member continuously interconnecting the second member ofthe third planetary gear set with the third member of the fourthplanetary gear set; a fifth interconnecting member continuouslyinterconnecting the third member of the third planetary gear set withthe second member of the fourth planetary gear set; and six torquetransmitting mechanisms selectively engageable to interconnect one ofthe first members, second members, and third members with at least oneof the first members, second members, third members, and a stationaryelement, and wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least nineforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 2. The transmission of claim 1wherein a first of the six torque transmitting mechanisms is selectivelyengageable to interconnect at least one of the input member, the thirdmember of the first planetary gear set, and the first member of thesecond planetary gear set with at least one of the second member of thethird planetary gear set and the third member of the fourth planetarygear set.
 3. The transmission of claim 2 wherein a second of the sixtorque transmitting mechanisms is selectively engageable to interconnectat least one of the input member, the third member of the firstplanetary gear set, and the first member of the second planetary gearset with the first member of the fourth planetary gear set.
 4. Thetransmission of claim 3 wherein a third of the six torque transmittingmechanisms is selectively engageable to interconnect the first member ofthe first planetary gear set with the stationary element.
 5. Thetransmission of claim 4 wherein a fourth of the six torque transmittingmechanisms is selectively engageable to interconnect at least one of thesecond member of the first planetary gear set and the second member ofthe second planetary gear set with the stationary element.
 6. Thetransmission of claim 5 wherein a fifth of the six torque transmittingmechanisms is selectively engageable to interconnect at least one of thethird member of the second planetary gear set and the first member ofthe third planetary gear set with the stationary element.
 7. Thetransmission of claim 6 wherein a sixth of the six torque transmittingmechanisms is selectively engageable to interconnect at least one of thesecond member of the third planetary gear set and the third member ofthe fourth planetary gear set with the stationary element.
 8. Thetransmission of claim 1 wherein the first members are sun gears, thesecond members are carrier members, and the third members are ringgears.
 9. The transmission of claim 1 wherein the input member iscontinuously interconnected with at least one of the third member of thefirst planetary gear set and the first member of the second planetarygear set and wherein the output member is continuously interconnectedwith at least one of the third member of the third planetary gear setand the second member of the fourth planetary gear set.
 10. Thetransmission of claim 1 wherein four of the torque transmittingmechanisms are brakes and two of the torque transmitting mechanisms areclutches.
 11. The transmission of claim 1 wherein the stationary elementis a transmission housing.
 12. A transmission comprising: an inputmember; an output member; first, second, third and fourth planetary gearsets each having first, second and third members, wherein the inputmember is continuously interconnected with at least one of the thirdmember of the first planetary gear set and the first member of thesecond planetary gear set and wherein the output member is continuouslyinterconnected with at least one of the third member of the thirdplanetary gear set and the second member of the fourth planetary gearset; a first interconnecting member continuously interconnecting thesecond member of the first planetary gear set with the second member ofthe second planetary gear set; a second interconnecting membercontinuously interconnecting the third member of the first planetarygear set with the first member of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the third member ofthe second planetary gear set with the first member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe third member of the fourth planetary gear set; a fifthinterconnecting member continuously interconnecting the third member ofthe third planetary gear set with the second member of the fourthplanetary gear set; a first torque transmitting mechanism selectivelyengageable to interconnect at least one of the input member, the thirdmember of the first planetary gear set, and the first member of thesecond planetary gear set with at least one of the second member of thethird planetary gear set and the third member of the fourth planetarygear set; a second torque transmitting mechanism selectively engageableto interconnect at least one of the input member, the third member ofthe first planetary gear set, and the first member of the secondplanetary gear set with the first member of the fourth planetary gearset; a third torque transmitting mechanism selectively engageable tointerconnect the first member of the first planetary gear set with astationary element; a fourth torque transmitting mechanism selectivelyengageable to interconnect at least one of the second member of thefirst planetary gear set and the second member of the second planetarygear set with the stationary element; a fifth torque transmittingmechanism selectively engageable to interconnect at least one of thethird member of the second planetary gear set and the first member ofthe third planetary gear set with the stationary element; and a sixthtorque transmitting mechanism selectively engageable to interconnect atleast one of the second member of the third planetary gear set and thethird member of the fourth planetary gear set with the stationaryelement, and wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least nineforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 13. The transmission of claim 12wherein the first members are sun gears, the second members are carriermembers, and the third members are ring gears.
 14. The transmission ofclaim 12 wherein the stationary element is a transmission housing.
 15. Atransmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having a sun gear, acarrier member, and a ring gear, wherein the input member iscontinuously interconnected with at least one of the ring gear of thefirst planetary gear set and the sun gear of the second planetary gearset and wherein the output member is continuously interconnected with atleast one of the ring gear of the third planetary gear set and thecarrier member of the fourth planetary gear set; a first interconnectingmember continuously interconnecting the carrier member of the firstplanetary gear set with the carrier member of the second planetary gearset; a second interconnecting member continuously interconnecting thering gear of the first planetary gear set with the sun gear of thesecond planetary gear set; a third interconnecting member continuouslyinterconnecting the ring gear of the second planetary gear set with thesun gear of the third planetary gear set; a fourth interconnectingmember continuously interconnecting the carrier member of the thirdplanetary gear set with the ring gear of the fourth planetary gear set;a fifth interconnecting member continuously interconnecting the ringgear of the third planetary gear set with the carrier member of thefourth planetary gear set; a first torque transmitting mechanismselectively engageable to interconnect at least one of the input member,the ring gear of the first planetary gear set, and the sun gear of thesecond planetary gear set with at least one of the carrier member of thethird planetary gear set and the ring gear of the fourth planetary gearset; a second torque transmitting mechanism selectively engageable tointerconnect at least one of the input member, the ring gear of thefirst planetary gear set, and the sun gear of the second planetary gearset with the sun gear of the fourth planetary gear set; a third torquetransmitting mechanism selectively engageable to interconnect the sungear of the first planetary gear set with a stationary element; a fourthtorque transmitting mechanism selectively engageable to interconnect atleast one of the carrier member of the first planetary gear set and thecarrier member of the second planetary gear set with the stationaryelement; a fifth torque transmitting mechanism selectively engageable tointerconnect at least one of the ring gear of the second planetary gearset and the sun gear of the third planetary gear set with the stationaryelement; and a sixth torque transmitting mechanism selectivelyengageable to interconnect at least one of the carrier member of thethird planetary gear set and the ring gear of the fourth planetary gearset with the stationary element, and wherein the torque transmittingmechanisms are selectively engageable in combinations of at least two toestablish at least nine forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 16. Thetransmission of claim 15 wherein the stationary element is atransmission housing.